Rapeseed and sunflower meal: a review on biotechnology status and challenges

Establishment of a rapeseed meal fermentation model for iturin A production by Bacillus amyloliquefaciens CX-20

Iturin A is an important broad-spectrum antifungal cyclic lipopeptide used as an ideal potential biological control agent. However, its application is limited mainly due to the producer strains' low productivity and the high production costs. Here, a potentially industrial strain Bacillus amyloliquefaciens CX-20 was proved to use low-cost rapeseed meal (RSM) as the sole source of all nutrients except the carbon source for the high productivity of iturin A. A fermentation model was first established to analyse the specific roles of different RSM components on iturin A production. Proteins and minerals in RSM were confirmed to play positive role, whereas fibre had negative effect. And the maximal concentration of iturin A was predicted to be more than 1.64 g l-1 by the established evaluation model. Moreover, submerged fermentation of B. amyloliquefaciens CX-20 demonstrated a strong ability to hydrolyse RSM and release water-soluble nutrients. This fermentation broth, a mixture of Bacillus, iturin A and RSM hydrolysate, could simultaneously combat clubroot disease and promote the growth of Brassica napus. In conclusion, this study provides a promising strategy to achieve full utilization of RSM for the production of a combination of value-added biological control agent and biofertilizer.

The Use of Upcycled Defatted Sunflower Seed Flour as a Functional Ingredient in Biscuits

Defatted sunflower seed flour (DSSF) is an upcycled by-product of sunflower oil extraction, rich in protein, fibre and antioxidants. This study assessed the instrumental and sensory quality of biscuits enriched with DSSF at 18% and 36% w/w as a replacement for wheat flour. Measurements included colour, texture, total phenolic content (TPC) and antioxidant capacity. Sensory analysis was carried out with Quantitative Descriptive Analysis (QDA). The inclusion of DSSF significantly increased the protein content of the biscuits, as well as the TPC and antioxidant capacity of the biscuits. The resulting products were significantly darker, less red and less yellow with increasing DSSF levels, while hardness (measured instrumentally) increased. Sensory results agreed with colour measurements, concluding that DSSF biscuits were more “Brown” than the control, and with texture measurements where biscuits with 36% DSSF had a significantly firmer bite. In addition, DSSF biscuits at 36% inclusion had higher QDA scores for “Off-note” and the lowest scores for “Crumbly” and “Crumb aeration”. DSSF biscuits at 18% inclusion were similar to the control in most parameters and should be considered for further developments. These results show the potential of the upcycled DSSF by-product as a novel, sustainable and healthy food ingredient.

Lavender- and lavandin-distilled straws: an untapped feedstock with great potential for the production of high-added value compounds and fungal enzymes

BACKGROUND

Lavender (Lavandula angustifolia) and lavandin (a sterile hybrid of L. angustifolia × L. latifolia) essential oils are among those most commonly used in the world for various industrial purposes, including perfumes, pharmaceuticals and cosmetics. The solid residues from aromatic plant distillation such as lavender- and lavandin-distilled straws are generally considered as wastes, and consequently either left in the fields or burnt. However, lavender- and lavandin-distilled straws are a potentially renewable plant biomass as they are cheap, non-food materials that can be used as raw feedstocks for green chemistry industry. The objective of this work was to assess different pathways of valorization of these straws as bio-based platform chemicals and fungal enzymes of interest in biorefinery.

RESULTS

Sugar and lignin composition analyses and saccharification potential of the straw fractions revealed that these industrial by-products could be suitable for second-generation bioethanol prospective. The solvent extraction processes, developed specifically for these straws, released terpene derivatives (e.g. τ-cadinol, β-caryophyllene), lactones (e.g. coumarin, herniarin) and phenolic compounds of industrial interest, including rosmarinic acid which contributed to the high antioxidant activity of the straw extracts. Lavender and lavandin straws were also suitable inducers for the secretion of a wide panel of lignocellulose-acting enzymes (cellulases, hemicellulases and oxido-reductases) from the white-rot model fungus Pycnoporus cinnabarinus. Interestingly, high amounts of laccase and several lytic polysaccharide monooxygenases were identified in the lavender and lavandin straw secretomes using proteomics.

CONCLUSIONS

The present study demonstrated that the distilled straws of lavender and lavandin are lignocellulosic-rich materials that can be used as raw feedstocks for producing high-added value compounds (antioxidants, aroma) and fungal oxidative enzymes, which represent opportunities to improve the decomposition of recalcitrant lignocellulose into biofuel. Hence, the structure and the physico-chemical properties of these straws clearly open new perspectives for use in biotechnological processes involving especially filamentous fungi. These approaches represent sustainable strategies to foster the development of a local circular bioeconomy.

Nutritional Value of Commercial Protein-Rich Plant Products

The goal of this work was to analyze nutritional value of various minimally processed commercial products of plant protein sources such as faba bean (Vicia faba), lupin (Lupinus angustifolius), rapeseed press cake (Brassica rapa/napus subsp. Oleifera), flaxseed (Linum usitatissimum), oil hemp seed (Cannabis sativa), buckwheat (Fagopyrum esculentum), and quinoa (Chenopodium quinoa). Basic composition and various nutritional components like amino acids, sugars, minerals, and dietary fiber were determined. Nearly all the samples studied could be considered as good sources of essential amino acids, minerals and dietary fiber. The highest content of crude protein (over 30 g/100 g DW) was found in faba bean, blue lupin and rapeseed press cake. The total amount of essential amino acids (EAA) ranged from 25.8 g/16 g N in oil hemp hulls to 41.5 g/16 g N in pearled quinoa. All the samples studied have a nutritionally favorable composition with significant health benefit potential. Processing (dehulling or pearling) affected greatly to the contents of analyzed nutrients.

Identification of genomic ATP binding cassette (ABC) transporter genes and Cd-responsive ABCs in Brassica napus

The plant ATP binding cassette (ABC) transporters are one of the integral membrane proteins responsible for uptake and allocation of a wide range of metabolites and xenobiotics including heavy metals (e.g. zinc, manganese and cadmium). They play multiple roles in plant growth, development and environmental stress responses. Although the ABC transporters have been identified in model plants such as Arabidopsis and rice, they are have not been annotated and identified in rapeseed (Brassica napus) and also, little is known about functionality of these metal transporters. B. napus is an important oil crop ranking the third largest source of vegetable oil worldwide. Importantly, it is long considered as a desirable candidate for phytoremediation owning to its massive dry weight productivity and moderate Cd accumulation. In this study, we identified 314 ABC protein genes from B. napus using bioinformatics and high-throughput sequencing. Eight subfamilies including ABCA-G and ABCI have been categorized. The ABCG proteins constitute the largest subfamily with 116 members, and the ABCB and ABCC subfamilies ranks second and third with 69 and 47 members, respectively. Analyses of ABCs in B. napus genome reveal that their evolutional expansion was through localized allele duplications. Most of the ABC genes (74.2%, 233/314) were validated by RNA-sequencing rapeseed seedlings. Among the 233 profiled BnaABCs, 132 genes were differentially expressed (>1.5 fold change, p < 0.05) and 84 genes were significantly induced under Cd stress. Analyses of specific cis-elements in the upstream of eight representative genes show diverse motifs, which potentially respond to environmental stress, hormone responsiveness and other development signals.

A Novel Approach for Microbial Synthesis of Enantiomerically Pure Whisky Lactones Based on Solid-State Fermentation

In this study, solid-state fermentation (SSF) was proposed as an alternative approach to obtain optically pure forms of one of the most common aroma compounds, whisky lactone. Filamentous fungi were used for enantioselective hydrolysis of a racemate of trans and cis whisky lactones, utilizing rapeseed cake as a growth medium. Among the tested fungi, Fusarium oxysporum AM13 and Papularia rosea AM17 were chosen for further studies. Various process parameters, including temperature, moisture content of solid media, and substrate concentration were optimized to maximize the efficiency of the kinetic resolution process. After optimization of the culture conditions (33 °C temperature, 60% moisture content, and substrate concentration of 3 mg/g oilseed cake), F. oxysporum AM13 resolved a mixture of trans-(+)-(4S,5R) and cis-(+)-(4R,5R) whisky lactones with enantiomeric excess (ee), ee > 99% and ee = 98%, respectively. This study presents an inexpensive and environmentally friendly method for the production of enantiomerically pure aroma lactones via the solid-state fermentation of oilseed cake. The results revealed that SSF is an effective method for acquiring highly valued and industrially demanded compounds with negligible economic cost.

Agricultural waste derived fuel from oil meal and waste cooking oil

Oil meal is a by-product of the oil industry (peanut meal, sesame meal, and camellia meal). Oil is extracted from seeds, and the leftover meal is then pelletized, and this process generates a large amount of waste oil meal in Taiwan. In this study, peanut meal, sesame meal, and camellia meal derived fuels were prepared from the waste oil meal with waste cooking oil. The combustion behaviors of the oil meal derived fuels were also investigated. The characteristics of the derived fuel made from oil meal with waste cooking oil showed that the ash content is less than 10% and its calorific value reached 5000 kcal/kg. Additionally, the activation energy of the oil meal and waste cooking oil was analyzed by the Kissinger method. The results show that the fuel prepared in this work from the oil meal mixed with waste cooking oil is suitable for use as an alternative fuel and also avoids food safety issues.

A Two-Step Bioconversion Process for Canolol Production from Rapeseed Meal Combining an Aspergillus niger Feruloyl Esterase and the Fungus Neolentinus lepideus

Rapeseed meal is a cheap and abundant raw material, particularly rich in phenolic compounds of biotechnological interest. In this study, we developed a two-step bioconversion process of naturally occurring sinapic acid (4-hydroxy-3,5-dimethoxycinnamic acid) from rapeseed meal into canolol by combining the complementary potentialities of two filamentous fungi, the micromycete Aspergillus niger and the basidiomycete Neolentinus lepideus. Canolol could display numerous industrial applications because of its high antioxidant, antimutagenic and anticarcinogenic properties. In the first step of the process, the use of the enzyme feruloyl esterase type-A (named AnFaeA) produced with the recombinant strain A. niger BRFM451 made it possible to release free sinapic acid from the raw meal by hydrolysing the conjugated forms of sinapic acid in the meal (mainly sinapine and glucopyranosyl sinapate). An amount of 39 nkat AnFaeA per gram of raw meal, at 55 °C and pH 5, led to the recovery of 6.6 to 7.4 mg of free sinapic acid per gram raw meal, which corresponded to a global hydrolysis yield of 68 to 76% and a 100% hydrolysis of sinapine. Then, the XAD2 adsorbent (a styrene and divinylbenzene copolymer resin), used at pH 4, enabled the efficient recovery of the released sinapic acid, and its concentration after elution with ethanol. In the second step, 3-day-old submerged cultures of the strain N. lepideus BRFM15 were supplied with the recovered sinapic acid as the substrate of bioconversion into canolol by a non-oxidative decarboxylation pathway. Canolol production reached 1.3 g/L with a molar yield of bioconversion of 80% and a productivity of 100 mg/L day. The same XAD2 resin, when used at pH 7, allowed the recovery and purification of canolol from the culture broth of N. lepideus. The two-step process used mild conditions compatible with green chemistry.

Utilizing pretreatment and fungal incubation to enhance the nutritional value of canola meal

AIMS

The objective of this study was to determine the optimal pretreatment and fungal strain to reduce glucosinolates (GLS), fibre and residual sugars while increasing the nutritional value of canola meal.

METHODS AND RESULTS

Submerged incubation conditions were used to evaluate four pretreatment methods (extrusion, hot water cook, dilute acid and dilute alkali) and three fungal cultures (Aureobasidium pullulans Y-2311-1, Fusarium venenatum NRRL-26139 and Trichoderma reesei NRRL-3653) in hexane-extracted (HE) and cold-pressed (CP) canola meal.

CONCLUSIONS

The combination of extrusion pretreatment followed by incubation with T. reesei resulted in the greatest overall improvement to HE canola meal, increasing protein to 51·5%, while reducing NDF, GLS and residual sugars to 18·6%, 17·2 μmol l^-1  g^-1 and 5% w/w, respectively. Extrusion pretreatment and incubation with F. venenatum performed the best with CP canola meal, resulting in 54·4% protein while reducing NDF, GLS and residual sugars to 11·6%, 6·7 μmol l^-1  g^-1 and 3·8% w/w respectively.

SIGNIFICANCE AND IMPACT OF THE STUDY

The work is significant in that it provides a method of reducing GLS (up to 98%) and neutral detergent fibre (up to 65%) while increasing the protein content (up to 45%) of canola meal. This novel pretreatment and submerged incubation process could be used to produce a canola product with higher nutritional value for livestock consumption.

Protection of protein from ruminal degradation by alkali-induced oxidation of chlorogenic acid in sunflower meal

Lactating ruminants require an adequate supply of absorbable amino acids for the synthesis of milk protein from two sources, that is crude protein (CP) synthesized microbially in the rumen and ruminally undegraded CP (RUP) from feed which can both be digested in the small intestine. Several chemical and physical methods have been identified as being effective in increasing the proportion of RUP of total CP of a feedstuff, yet there is a continuing need for developing and establishing methods which protect feed protein from ruminal degradation with acceptable expenditure of labour and other costs. The objective of this study was to identify and quantify effects of and interactions between chlorogenic acid and protein in solvent-extracted sunflower meal (SFM) as induced by alkali treatment. Response surface methodology was employed to investigate the influence of pH, reaction time and drying temperature on the resulting SFM and, subsequently, its protein value for ruminants estimated from laboratory values. For this purpose, alkali-treated SFM was subjected to a fractionation of feed CP according to the Cornell net carbohydrate and protein system as a basis for estimating RUP at different assumed ruminal passage rates (K_p ). To estimate the intestinal digestibility of the treated SFM and its RUP, a three-step enzymatic in vitro procedure was applied. Alkaline treatment of SFM increased RUP values with factors ranging from approximately 3 (K_p =.08/hr) to 12 (K_p =.02/hr). Furthermore, the intestinal digestibility of the alkali-treated SFM was enhanced by approximately 10% compared to untreated SFM. Increasing pH and reaction time led to both increasing RUP values and intestinal digestibility. In conclusion, a targeted alkaline treatment of naturally occurring compounds in feedstuffs might be a promising approach to provide high-RUP feeds for ruminants which, at the same time, have improved intestinal digestibility values.

Worldwide Mycotoxins Exposure in Pig and Poultry Feed Formulations

The purpose of this review is to present information about raw materials that can be used in pig and poultry diets and the factors responsible for variations in their mycotoxin contents. The levels of mycotoxins in pig and poultry feeds are calculated based on mycotoxin contamination levels of the raw materials with different diet formulations, to highlight the important role the stage of production and the raw materials used can have on mycotoxins levels in diets. Our analysis focuses on mycotoxins for which maximum tolerated levels or regulatory guidelines exist, and for which sufficient contamination data are available. Raw materials used in feed formulation vary considerably depending on the species of animal, and the stage of production. Mycotoxins are secondary fungal metabolites whose frequency and levels also vary considerably depending on the raw materials used and on the geographic location where they were produced. Although several reviews of existing data and of the literature on worldwide mycotoxin contamination of food and feed are available, the impact of the different raw materials used on feed formulation has not been widely studied.

Physicochemical Properties Analysis and Secretome of Aspergillus niger in Fermented Rapeseed Meal

The nutrient digestibility and feeding value of rapeseed meal (RSM) for non-ruminant animals is poor due to the presence of anti-nutritional substances such as glucosinolate, phytic acid, crude fiber etc. In the present study, a solid state fermentation (SSF) using Aspergillus niger was carried out with the purpose of improving the nutritional quality of RSM. The chemical composition and physicochemical properties of RSM before and after fermentation were compared. To further understand possible mechanism of solid state fermentation, the composition of extracellular enzymes secreted by Aspergillus niger during fermentation was analysed using two-dimentional difference gel electrophoresis (2D-DIGE) combined with matrix assisted laser desorption ionization-time of flight-mass spectrometer (MALDI-TOF-MS). Results of the present study indicated that SSF had significant effects on chemical composition of RSM. The fermented rapeseed meal (FRSM) contained more crude protein (CP) and amino acid (AA) (except His) than unfermented RSM. Notably, the small peptide in FRSM was 2.26 time larger than that in unfermented RSM. Concentrations of anti-nutritional substrates in FRSM including neutral detergent fiber (NDF), glucosinolates, isothiocyanate, oxazolidithione, and phytic acid declined (P < 0.05) by 13.47, 43.07, 55.64, 44.68 and 86.09%, respectively, compared with unfermented RSM. A. niger fermentation disrupted the surface structure, changed macromolecular organic compounds, and reduced the protein molecular weights of RSM substrate. Total proteins of raw RSM and FRSM were separated and 51 protein spots were selected for mass spectrometry according to 2D-DIGE map. In identified proteins, there were 15 extracellular hydrolases secreted by A. niger including glucoamylase, acid protease, beta-glucanase, arabinofuranosidase, xylanase, and phytase. Some antioxidant related enzymes also were identified. These findings suggested that A. niger is able to secrete many extracellular degradation enzymes (especially lignocellulosic hydrolyzing enzymes, acid proteases and phytase) during fermentation of RSM, thus altering chemical composition and physicochemical properties of RSM.

Amino acid, phosphorus, and energy digestibility of Aspergillus niger fermented rapeseed meal fed to growing pigs

Fermented rapeseed meal (FRSM) contains greater levels of protein and less glucosinolates, NDF, and phytic acid than rapeseed meal (RSM) and might be an attractive feedstuff for swine, but its nutritional value has been poorly characterized. The aim of this study was to evaluate the nutritional value of RSM fermented by for growing pigs. In Exp. 1, 6 barrows (21.20 ± 1.47 kg initial BW) fitted with a T-cannula in the distal ileum were allotted to a repeated 3 × 3 Latin square with 3 diets and 3 periods per square to determine the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of CP and AA. A N-free diet and 2 diets containing RSM or FRSM as the only source of AA were formulated. Results indicated that there was no difference in AID and SID of CP and most AA between FRSM and RSM. However, the AID of 2 indispensable AA (Lys and Met) and 3 dispensable AA (Asp, Gly, and Tyr) were greater (P < 0.05) for FRSM than for RSM. The SID of only 2 dispensable AA (Gly and Tyr) were greater (P < 0.05) for FRSM than for RSM. In Exp. 2, 16 barrows (32.57 ± 2.67 kg initial BW) were allotted to 2 diets formulated to contain RSM or FRSM as the sole source of P to determine the apparent total tract digestibility (ATTD) of P. The ATTD and standardized total tract digestibility (STTD) of P in FRSM were 72.10 and 77.31%, respectively. These values were greater (P < 0.01) than in RSM (34.79 and 41.34%, respectively). In Exp. 3, 24 growing barrows (32.23 ± 1.33 kg initial BW) were fed 3 diets with 8 replicate pigs per diet to measure concentration of DE and ME of FRSM. A corn diet consisting of 98.40% corn was formulated and 2 additional diets were formulated by mixing corn with 35% RSM or FRSM. The DE and ME in FRSM (2,887 and 2,650 kcal/kg of DM, respectively) were greater (P < 0.05) than those in RSM (2,609 and 2,328 kcal/kg of DM, respectively). In summary, solid-state fermentation of RSM by has a greater nutritional value than RSM and is a promising alternative high-quality protein source.

Identification, duplication, evolution and expression analyses of caleosins in Brassica plants and Arabidopsis subspecies

Caleosins are a class of Ca(2+) binding proteins that appear to be ubiquitous in plants. Some of the main proteins embedded in the lipid monolayer of lipid droplets, caleosins, play critical roles in the degradation of storage lipids during germination and in lipid trafficking. Some of them have been shown to have histidine-dependent peroxygenase activity, which is believed to participate in stress responses in Arabidopsis. In the model plant Arabidopsis thaliana, caleosins have been examined extensively. However, little is known on a genome-wide scale about these proteins in other members of the Brassicaceae. In this study, 51 caleosins in Brassica plants and Arabidopsis lyrata were investigated and analyzed in silico. Among them, 31 caleosins, including 7 in A. lyrata, 11 in Brassica oleracea and 13 in Brassica napus, are herein identified for the first time. Segmental duplication was the main form of gene expansion. Alignment, motif and phylogenetic analyses showed that Brassica caleosins belong to either the H-family or the L-family with different motif structures and physicochemical properties. Our findings strongly suggest that L-caleosins are evolved from H-caleosins. Predicted phosphorylation sites were differentially conserved in H-caleosin and L-caleosins, respectively. 'RY-repeat' elements and phytohormone-related cis-elements were identified in different caleosins, which suggest diverse physiological functions. Gene structure analysis indicated that most caleosins (38 out of 44) contained six exons and five introns and their intron phases were highly conserved. Structurally integrated caleosins, such as BrCLO3-3 and BrCLO4-2, showed high expression levels and may have important roles. Some caleosins, such as BrCLO2 and BoCLO8-2, lost motifs of the calcium binding domain, proline knot, potential phosphorylation sites and haem-binding sites. Combined with their low expression, it is suggested that these caleosins may have lost function.

Statistical optimization of antifungal iturin A production from Bacillus amyloliquefaciens RHNK22 using agro-industrial wastes

Biosurfactants are secondary metabolites with surface active properties and have wide application in agriculture, industrial and therapeutic products. The present study was aimed to screen bacteria for the production of biosurfactant, its characterization and development of a cost effective media formulation for iturin A production. A total of 100 bacterial isolates were isolated from different rhizosphere soil samples by enrichment culture method and screened for biosurfactant activity. Twenty isolates were selected for further studies based on their biosurfactant activity [emulsification index (EI%), emulsification assay (EA), surface tension (ST) reduction] and antagonistic activity. Among them one potential isolate Bacillus sp. RHNK22 showed good EI% and EA with different hydrocarbons tested in this study. Using biochemical methods and 16S rRNA gene sequence, it was identified as Bacillus amyloliquefaciens. Presence of iturin A in RHNK22 was identified by gene specific primers and confirmed as iturin A by FTIR and HPLC. B. amyloliquefaciens RHNK22 exhibited good surface active properties and antifungal activity against Sclerotium rolfsii and Macrophomina phaseolina. For cost-effective production of iturin A, 16 different agro-industrial wastes were screened as substrates, and Sunflower oil cake (SOC) was favouring high iturin A production. Further, using response surface methodology (RSM) model, there was a 3-fold increase in iturin A production (using SOC 4%, inoculum size 1%, at pH 6.0 and 37 °C temperature in 48 h). This is the first report on using SOC as a substrate for iturin A production.

Effects of Aspergillus niger fermented rapeseed meal on nutrient digestibility, growth performance and serum parameters in growing pigs

The aim of the present study was to investigate the influences of Aspergillus niger fermented rapeseed meal (FRSM) on growth performance and nutrient digestibility of growing pigs. A total of 72 growing pigs (body weight = 40.8 ± 2.1 kg) were used in feeding trials, lasting for up to 42 days, and were randomly allotted to one of three diets, including a corn-soybean meal control diet as well as two experimental diets containing 10% unfermented rapeseed meal (RSM) or 10% FRSM. The results showed that average daily gain and feed conversion ratio of pigs fed FRSM were superior (P < 0.05) to that of pigs fed unfermented RSM and did not differ from the control. Pigs fed control diet had higher (P < 0.05) total tract apparent digestibility for dry matter, protein, calcium and phosphorus than pigs fed unfermented RSM diet and did not differ from the FRSM diet. Pigs fed FRSM had lower levels (P < 0.05) of serum aspartate transaminase compared to unfermented RSM. In conclusion, solid state fermentation using Aspergillus niger may improve the growth performance and nutrient digestibility of RSM for pigs and FRSM is a promising alternative protein for pig production.

Canola meal as a novel substrate for β-glucosidase production by Trichoderma viride: application of the crude extract to biomass saccharification

β-Glucosidases are important enzymes with significant prospects in the industrial biotechnology, including their use in biomass hydrolysis for bioethanol production. In this study, the use of canola meal as carbon source for β-glucosidase production by a Trichoderma viride strain in submerged fermentation was evaluated by applying central composite design and response surface methodology to optimize the production process. This statistical approach was also used to improve the passion fruit peel hydrolysis by T. viride crude extract. The model developed 3.6-fold increased β-glucosidase activity. The culture conditions that resulted in the highest β-glucosidase levels were a substrate concentration of 2.9 %, pH of medium 4.2 and cultivation time of 206 h. The β-glucosidases produced under optimal conditions showed attractive properties for industrial applications, such as activity at high temperatures and stability at 55 °C and over a wide pH range. In addition, the enzymatic hydrolysis of passion fruit peel by T. viride crude extract was very promising, resulting in glucose yields of 66.4 %. This study, therefore, presents canola meal as an inexpensive and attractive substrate for the production of microbial β-glucosidases.

Improvement of Omega-3 Docosahexaenoic Acid Production by Marine Dinoflagellate Crypthecodinium cohnii Using Rapeseed Meal Hydrolysate and Waste Molasses as Feedstock

Rapeseed meal and waste molasses are two important agro-industrial by-products which are produced in large quantities. In this study, solid state fermentation and fungal autolysis were performed to produce rapeseed meal hydrolysate (RMH) using fungal strains of Aspergillus oryzae, Penicillium oxalicum and Neurospora crassa. The hydrolysate was used as fermentation feedstock for heterotrophic growth of microalga Crypthecodinium cohnii that produce docosahexaenoic acid (DHA). The addition of waste molasses as a supplementary carbon source greatly increased the biomass and DHA yield. In the batch fermentations using media composed of diluted RMH (7%) and 1-9% waste molasses, the highest biomass concentration and DHA yield reached 3.43 g/L and 8.72 mg/L, respectively. The algal biomass produced from RMH and molasses medium also had a high percentage of DHA (22-34%) in total fatty acids similar to that of commercial algal biomass. RMH was shown to be rich in nitrogen supply comparable to the commercial nitrogen feedstock like yeast extract. Using RMH as sole nitrogen source, waste molasses excelled other carbon sources and produced the highest concentration of biomass. This study suggests that DHA production of the marine dinoflagellate C. cohnii could be greatly improved by concomitantly using the cheap by-products rapeseed meal hydrolysate and molasses as alternative feedstock.

A dry platform for separation of proteins from biomass-containing polysaccharides, lignin, and polyphenols

License to mill: Proteins were continuously extracted from polysaccharides, lignin, and polyphenol by combining ultrafine milling with electrostatic separation. Such a fractionation process does not involve any solvent, catalyst, or external source of heating. In addition, this dry process is compatible with downstream enzymatic reactions, thus opening an attractive route for producing valuable chemicals from biomass.

Solid state fermentation of rapeseed cake with Aspergillus niger for degrading glucosinolates and upgrading nutritional value

BACKGROUND

Rapeseed cake is a good source of protein for animal feed but its utilization is limited due to the presence of anti-nutritional substances, such as glucosinolates (Gls), phytic acid, tannins etc. In the present study, a solid state fermentation (SSF) using Aspergillus niger was carried out with the purpose of degrading glucosinolates and improving the nutritional quality of rapeseed cake (RSC). The effects of medium composition and incubation conditions on the Gls content in fermented rapeseed cake (FRSC) were investigated, and chemical composition and amino acid in vitro digestibility of RSC substrate fermented under optimal conditions were determined.

RESULTS

After 72 h of incubation at 34°C, a 76.89% decrease in Gls of RSC was obtained in solid medium containing 70% RSC, 30% wheat bran at optimal moisture content 60% (w/w). Compared to unfermented RSC, trichloroacetic acid soluble protein (TCA-SP), crude protein and ether extract contents of the FRSC were increased (P < 0.05) 103.71, 23.02 and 23.54%, respectively. As expected, the contents of NDF and phytic acid declined (P < 0.05) by 9.12 and 44.60%, respectively. Total amino acids (TAA) and essential amino acids (EAA) contents as well as AA in vitro digestibility of FRSC were improved significantly (P < 0.05). Moreover, the enzyme activity of endoglucanase, xylanase, acid protease and phytase were increased (P < 0.05) during SSF.

CONCLUSIONS

Our results indicate that the solid state fermentation offers an effective approach to improving the quality of proteins sources such as rapeseed cake.

Transcriptomic basis of functional difference and coordination between seeds and the silique wall of Brassica napus during the seed-filling stage

The silique of oilseed rape (Brassica napus) is a composite organ including seeds and the silique wall (SW) that possesses distinctly physiological, biochemical and functional differentiations. Yet, the molecular events controlling such differences between the SW and seeds, as well as their coordination during silique development at transcriptional level are largely unknown. Here, we identified large sets of differentially expressed genes in the SW and seeds of siliques at 21-22 days after flowering with a Brassica 95K EST microarray. At this particular stage, there were 3278 SW preferentially expressed genes and 2425 seed preferentially expressed genes. Using the MapMan visualization software, genes differentially regulated in various metabolic pathways and sub-pathways between the SW and seeds were revealed. Photosynthesis and transport-related genes were more actively transcripted in the SW, while those involved in lipid metabolism were more active in seeds during the seed filling stage. On the other hand, genes involved in secondary metabolisms were selectively regulated in the SW and seeds. Large numbers of transcription factors were identified to be differentially expressed between the SW and seeds, suggesting a complex pattern of transcriptional control in these two organs. Furthermore, most genes discussed in categories or pathways showed a similar expression pattern through 21 DAF to 42 DAF. Our results thus provide insights into the coordination of seeds and the SW in the developing silique at the transcriptional levels, which will facilitate the functional studies of important genes for improving B. napus seed productivity and quality.

Characterization of the factors that influence sinapine concentration in rapeseed meal during fermentation

We analyzed and compared the difference in sinapine concentration in rapeseed meal between the filamentous fungus, Trametes sp 48424, and the yeast, Saccharomyces cerevisiae, in both liquid and solid-state fermentation. During liquid and solid-state fermentation by Trametes sp 48424, the sinapine concentration decreased significantly. In contrast, the liquid and solid-state fermentation process by Saccharomyces cerevisiae just slightly decreased the sinapine concentration (P ≤ 0.05). After the solid-state fermented samples were dried, the concentration of sinapine in rapeseed meal decreased significantly in Saccharomyces cerevisiae. Based on the measurement of laccase activity, we observed that laccase induced the decrease in the concentration of sinapine during fermentation with Trametes sp 48424. In order to eliminate the influence of microorganisms and the metabolites produced during fermentation, high moisture rapeseed meal and the original rapeseed meal were dried at 90°C and 105°C, respectively. During drying, the concentration of sinapine in high moisture rapeseed meal decreased rapidly and we obtained a high correlation coefficient between the concentration of sinapine and loss of moisture. Our results suggest that drying and enzymes, especially laccase that is produced during the solid-state fermentation process, may be the main factors that affect the concentration of sinapine in rapeseed meal.

Direct bio-utilization of untreated rapeseed meal for effective iturin A production by Bacillus subtilis in submerged fermentation

The feasibility of using untreated rapeseed meal as a nitrogen source for iturin A production by Bacillus subtilis 3-10 in submerged fermentation was first evaluated by comparison with two different commercial nitrogen sources of peptone and ammonium nitrate. A significant promoting effect of rapeseed meal on iturin A production was observed and the maximum iturin A concentration of 0.60 g/L was reached at 70 h, which was 20% and 8.0 fold higher than that produced from peptone and ammonium nitrate media, respectively. It was shown that rapeseed meal had a positive induction effect on protease secretion, contributing to the release of soluble protein from low water solubility solid rapeseed meal for an effective supply of available nitrogen during fermentation. Moreover, compared to raw rapeseed meal, the remaining residue following fermentation could be used as a more suitable supplementary protein source for animal feed because of the great decrease of major anti-nutritional components including sinapine, glucosinolate and its degradation products of isothiocyanate and oxazolidine thione. The results obtained from this study demonstrate the potential of direct utilization of low cost rapeseed meal as a nitrogen source for commercial production of iturin A and other secondary metabolites by Bacillus subtilis.

Improved Rifamycin B Production by Nocardia mediterranei MTCC 14 under Solid-State Fermentation through Process Optimization

Optimization of various production parameters using response surface methodology (RSM) was performed to assess maximum yield of rifamycin B from Nocardia mediterranei MTCC 14. Plackett-Burman design test was applied to determine the significant effects of various production parameters such as glucose, maltose, ribose, galactose, beef extract, peanut meal, ammonium chloride, ammonium sulphate, barbital, pH, and moisture content on production of rifamycin B. Among the eleven variables tested, galactose, ribose, glucose, and pH were found to have significant effect on rifamycin B production. Optimum levels of the significant variables were decided by using a central composite design. The most appropriate condition for production of rifamycin B was found to be a single step production at galactose (8% w/w), ribose (3% w/w), glucose (9% w/w), and pH (7.0). At these optimum production parameters, the maximum yield of rifamycin B obtained experimentally (9.87 g/kgds dry sunflower oil cake) was found to be very close to its predicted value of 10.35 g/kgds dry sunflower oil cake. The mathematical model developed was found to fit greatly with the experimental data of rifamycin B production.

Identification of heat responsive genes in Brassica napus siliques at the seed-filling stage through transcriptional profiling

High temperature stress results in yield loss and alterations to seed composition during seed filling in oilseed rape (Brassica napus). However, the mechanism underlying this heat response is poorly understood. In this study, global transcription profiles of 20 d-old siliques of B. napus were analyzed after heat stress using a Brassica 95k EST microarray. The up-regulated genes included many HSF/HSP transcripts and other heat-related marker genes, such as ROF2, DREB2a, MBF1c and Hsa32, reflecting the conservation of key heat resistance factors among plants. Other up-regulated genes were preferentially expressed in heat-stressed silique walls or seeds, including some transcription factors and potential developmental regulators. In contrast, down-regulated genes differed between the silique wall and seeds and were largely tied to the biological functions of each tissue, such as glucosinolate metabolism in the silique wall and flavonoid synthesis in seeds. Additionally, a large proportion (one-third) of these differentially expressed genes had unknown functions. Based on these gene expression profiles, Arabidopsis mutants for eight heat-induced Brassica homologous genes were treated with different heat stress methods, and thermotolerance varied with each mutation, heat stress regimen and plant development stage. At least two of the eight mutants exhibited sensitivity to the heat treatments, suggesting the importance of the respective genes in responding to heat stress. In summary, this study elucidated the molecular bases of the heat responses in siliques during later reproductive stages and provides valuable information and gene resources for the genetic improvement of heat tolerance in oilseed rape breeding.

Biorefinery development through utilization of biodiesel industry by-products as sole fermentation feedstock for 1,3-propanediol production

Rapeseed meal (RSM) hydrolysate was evaluated as substitute for commercial nutrient supplements in 1,3-propanediol (PDO) fermentation using the strain Clostridium butyricum VPI 1718. RSM was enzymatically converted into a generic fermentation feedstock, enriched in amino acids, peptides and various micro-nutrients, using crude enzyme consortia produced via solid state fermentation by a fungal strain of Aspergillus oryzae. Initial free amino nitrogen concentration influenced PDO production in batch cultures. RSM hydrolysates were compared with commercial nutrient supplements regarding PDO production in fed-batch cultures carried out in a bench-scale bioreactor. The utilization of RSM hydrolysates in repeated batch cultivation resulted in a PDO concentration of 65.5 g/L with an overall productivity of 1.15 g/L/h that was almost 2 times higher than the productivity achieved when yeast extract was used as nutrient supplement.

Supplemental macronutrients and microbial fermentation products improve the uptake and transport of foliar applied zinc in sunflower (Helianthus annuus L.) plants. Studies utilizing micro X-ray florescence

Enhancing nutrient uptake and the subsequent elemental transport from the sites of application to sites of utilization is of great importance to the science and practical field application of foliar fertilizers. The aim of this study was to investigate the mobility of various foliar applied zinc (Zn) formulations in sunflower (Helianthus annuus L.) and to evaluate the effects of the addition of an organic biostimulant on phloem loading and elemental mobility. This was achieved by application of foliar formulations to the blade of sunflower (H. annuus L.) and high-resolution elemental imaging with micro X-ray fluorescence (μ-XRF) to visualize Zn within the vascular system of the leaf petiole. Although no significant increase of total Zn in petioles was determined by inductively-coupled plasma mass-spectrometer, μ-XRF elemental imaging showed a clear enrichment of Zn in the vascular tissues within the sunflower petioles treated with foliar fertilizers containing Zn. The concentration of Zn in the vascular of sunflower petioles was increased when Zn was applied with other microelements with EDTA (commercial product Kick-Off) as compared with an equimolar concentration of ZnSO4 alone. The addition of macronutrients N, P, K (commercial product CleanStart) to the Kick-Off Zn fertilizer, further increased vascular system Zn concentrations while the addition of the microbially derived organic biostimulant "GroZyme" resulted in a remarkable enhancement of Zn concentrations in the petiole vascular system. The study provides direct visualized evidence for phloem transport of foliar applied Zn out of sites of application in plants by using μ-XRF technique, and suggests that the formulation of the foliar applied Zn and the addition of the organic biostimulant GroZyme increases the mobility of Zn following its absorption by the leaf of sunflower.

Canola Cake as a Potential Substrate for Proteolytic Enzymes Production by a Selected Strain of Aspergillus oryzae: Selection of Process Conditions and Product Characterization

Oil cakes have excellent nutritional value and offer considerable potential for use in biotechnological processes that employ solid-state fermentation (SSF) for the production of high value products. This work evaluates the feasibility of using canola cake as a substrate for protease production by a selected strain of Aspergillus oryzae cultivated under SSF. The influences of the following process parameters were considered: initial substrate moisture content, incubation temperature, inoculum size, and pH of the buffer used for protease extraction and activity analysis. Maximum protease activity was obtained after cultivating Aspergillus oryzae CCBP 001 at 20°C, using an inoculum size of 10(7) spores/g in canola cake medium moistened with 40 mL of water to 100 g of cake. Cultivation and extraction under selected conditions increased protease activity 5.8-fold, compared to the initial conditions. Zymogram analysis of the enzymatic extract showed that the protease molecular weights varied between 31 and 200 kDa. The concentrated protease extract induced clotting of casein in 5 min. The results demonstrate the potential application of canola cake for protease production under SSF and contribute to the technological advances needed to increase the efficiency of processes designed to add value to agroindustrial wastes.